Tunable asymmetric spin splitting by black phosphorus sandwiched epsilon-near-zero-metamaterial in the terahertz region

In-plane photonic spin splitting effect is investigated in tunneling terahertz waves through an epsilon-near-zero metamaterial sandwiched between monolaycr black phosphorus (BP). The strong in-plane anisotropy of BP layers will induce in-plane asymmetric spin splitting. The asymmetric spin splitting can be flexibly tuned by the angles between the incident plane and the armchair crystalline directions of the top and bottom BP layers. i.e., phi(1) and phi(2). Based on this an angle-resolved barcode-encryption scheme is discussed. For the special case of phi(1) = phi(2) = 0 or 90 degrees, the transmitted beam undergoes Goos-Hanchen shift, which varies with the carrier density of BP. We believe these findings can facilitate the development of novel optoclectronic devices in the Terahertz region. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement